Method for regulating the engine torque of an internal combustion engine in order to change the gear ratio

Abstract

One aspect of the invention relates to a method (100) for regulating the engine torque produced by an internal combustion engine of a powertrain provided with a mechanical gearbox, a mechanical clutch and control means, the method (100) being remarkable in that, during the acceleration phase of the powertrain, it comprises the following steps carried out by the control means: • Detecting (101) a desire to shift from a gear ratio N to a higher gear ratio N+n; • Degrading (102) the nominal spark advances of the internal combustion engine so as to reduce the engine torque produced by the internal combustion engine.

Description

METHOD FOR REGULATING THE MOTOR TORQUE OF AN INTERNAL COMBUSTION ENGINE TO PERFORM A GEAR RATIO CHANGE DESCRIPTION TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a method for regulating engine torque produced by an internal combustion engine. The invention finds a particularly interesting, but not exclusive, application in the field of engine torque regulation for a two-wheeled vehicle. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] It is known from two-wheeled vehicles equipped with an internal combustion engine, a mechanical gearbox without an actuator, and a mechanical clutch without an actuator.

[0003] On this type of vehicle, during acceleration, the driver can, without using the clutch, shift from a gear ratio N, for example equal to 2, to a higher gear ratio N+1, namely 3 in the example described.

[0004] To shift from a lower to a higher gear, it is necessary to reduce the stress on the gearbox gears by reducing the engine torque produced by the internal combustion engine. To achieve this, engine control systems control the interruption of fuel injection into the internal combustion engine cylinders and / or the interruption of spark production at the internal combustion engine's spark plugs.

[0005] Thus, as illustrated in Figure 1 showing an engine torque profile 1, when a gear change is detected, a cut-off of fuel injection and / or spark production, indicated by point 2, occurs. This cut-off of fuel injection and / or spark production causes a sudden drop in the engine torque produced by the internal combustion engine. The engine torque then abrupt shift from a positive torque to a negative torque generated by losses in the internal combustion engine, resulting in uncomfortable jolts for the driver. SUMMARY OF THE INVENTION

[0006] The invention offers a solution to the problem mentioned above, by proposing a method allowing, without using a clutch, for changing a gear ratio that is more comfortable for the driver.

[0007] In this context, the invention, in its broadest sense, relates to a method for regulating engine torque produced by an internal combustion engine in a powertrain equipped with a mechanical gearbox, a mechanical clutch, and control means. The method, according to this aspect of the invention, is remarkable in that, during the acceleration phase of the powertrain, it comprises the steps, executed by the control means, of Detect a desire to move from a speed ratio N to a higher speed ratio N+n; Degrade the nominal ignition advances of the internal combustion engine so as to decrease the engine torque produced by the internal combustion engine.

[0008] Thus, by degrading the nominal ignition advances of the internal combustion engine, rather than abruptly cutting off the fuel injection into the cylinders of the internal combustion engine and / or cutting off the sparks at the spark plugs of the internal combustion engine, the engine torque is reduced so as to optimize the torque reduction to allow a gradual and smooth gear change.

[0009] In addition to the characteristics mentioned in the preceding paragraph, the process according to this aspect of the invention may have one or more complementary characteristics from among the following, considered individually or according to all technically possible combinations.

[0010] According to a non-limiting aspect of the invention, the nominal ignition advances are degraded by applying an ignition advance regulation profile. Thus, engine torque is reduced through an adjustable ignition advance profile which optimizes the torque reduction to allow for smooth and progressive gear changes.

[0011] According to a non-limiting aspect of the invention, the nominal ignition advances are degraded until the engine torque is between a minimum torque threshold and a maximum torque threshold. The engine torque is thus reduced to allow the disengagement of the lower gear N and the re-engagement of the higher gear N+n in a range around zero torque.

[0012] According to a non-limiting aspect of the invention, the minimum torque threshold is less than ONm and the maximum torque threshold is greater than ONm.

[0013] According to a non-limiting aspect of the invention, the ignition advance regulation profile comprises: During an initial period of time, a sudden degradation of the nominal ignition advances; During a second time window following the first time window, a progressive degradation ramp of said ignition advances until the engine torque is between the minimum torque threshold and the maximum torque threshold; During a third time window successive to said second time window, an operating profile during which the motor torque is between the minimum torque threshold and the maximum torque threshold.

[0014] According to a non-limiting aspect of the invention, the ignition advance regulation profile includes, during a fourth time window successive to the third time window, a progressive catch-up ramp for the nominal ignition advances.

[0015] Another aspect of the invention relates to a vehicle comprising a powertrain equipped with an internal combustion engine, a mechanical gearbox, a mechanical clutch, and control means. The vehicle according to this aspect of the invention is remarkable in that the control means are arranged to perform the steps of the process according to any one of the aforementioned aspects of the invention.

[0016] Another non-limiting aspect of the invention relates to a computer program product downloadable from a communication network and / or saved on a computer-readable and / or processor-executable medium, said computer program product being notable in that it includes program code instructions for implementing the method according to any of the aforementioned aspects of the invention, when the program is executed on a computer.

[0017] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0018] The figures are presented for illustrative purposes only and are in no way limiting to the invention.

[0019] [Fig. 1] illustrates a torque profile of an internal combustion engine according to the state of the art.

[0020] [Fig. 2] illustrates the steps of a method for regulating motor torque according to a non-limiting aspect of the invention.

[0021] [Fig. 3] illustrates an ignition advance regulation profile and a motor torque correlated to said ignition advance regulation profile according to a non-limiting aspect of the invention. DETAILED DESCRIPTION

[0022] Figure 2 shows a non-limiting example of an embodiment of a method 100 for regulating motor torque according to a non-limiting aspect of the invention.

[0023] This engine torque can be produced by an internal combustion engine in a two-wheeled vehicle powertrain. This powertrain may also include a mechanical gearbox without an actuator, a mechanical clutch without an actuator, and means for controlling the powertrain.

[0024] During the acceleration phase of the powertrain and the request for a gear change, in other words when the driver accelerates and operates his gear selector, the process 100 includes a first step, executed by the engine control means, of detecting 101 a desire to move from a gear ratio N, for example equal to two, to a higher gear ratio N+n, for example equal to three.

[0025] This desire to change gear ratio corresponds to pulling on the gear selector and can be identified by a position sensor of a gear selector included in the two-wheeled vehicle, then transmitted to the engine control means.

[0026] As soon as the intention to move from a speed ratio N to a higher speed ratio N+n is detected by the engine control means, the latter perform a step of degrading 102 the nominal ignition advances of the internal combustion engine.

[0027] Nominal ignition timing is determined by the manufacturer and corresponds to the angle of the crankshaft before top dead center (TDC) at which a spark is produced at the spark plug. This angle is usually between 15° and 45° TDC.

[0028] By reducing the nominal ignition timing, the engine torque produced by the internal combustion engine is decreased. The stresses applied to the gears and shafts of the gearbox are therefore reduced, making gear changes easier.

[0029] According to a non-limiting example embodiment, the nominal ignition advances are degraded by applying an ignition advance regulation profile P1 conforming to that illustrated in figure 3.

[0030] Figure 3 also shows a P2 engine torque profile correlated with the P1 ignition advance regulation profile.

[0031] According to the illustrated example, the ignition advance regulation profile P1 models a sudden degradation of the nominal ignition advances during a first time window T1. This sudden degradation of the nominal ignition advances is almost instantaneous and results in a sudden reduction of engine torque.

[0032] This first time window T1 is followed by a second time window T2. During this second time window T2, a progressive degradation ramp of the ignition timing is applied. This degradation ramp continues until the engine torque is between a minimum torque threshold S1 and a maximum torque threshold S2. Thus, compared to the state of The technique involves reducing the engine torque in two stages in order to decrease the shaking phenomenon present in the prior art.

[0033] In this non-limiting example of implementation, the minimum torque threshold S1 is -5Nm and the maximum torque threshold S2 is +5Nm.

[0034] This second time window T2 is followed by a third time window T3. During this third time window T3, an operating profile is applied in which the motor torque is between the minimum torque threshold S1 and the maximum torque threshold S2.

[0035] According to a non-limiting example of an embodiment, the operating profile during which the engine torque is between the minimum torque threshold S1 and the maximum torque threshold S2 corresponds, for each cylinder of the internal combustion engine, to the production of a spark at the spark plug occurring between 0° and +15° after the top dead center of a piston of said cylinder.

[0036] Advantageously, during this operating profile, the engine torque is virtually stable and close to zero. The forces applied to the gears and shafts of the gearbox are reduced when the torque produced by the internal combustion engine is close to zero. Gear changes are therefore easier during this operating profile.

[0037] Finally, once the gear change has been made, the ignition timing profile models a gradual ramp-up of the nominal ignition timing over a fourth time window T4, following the third time window T3. Thus, the engine torque desired by the driver is once again applied.

[0038] The various aspects of the invention mentioned above offer numerous advantages. Among these are: Facilitate gear changes; Improve driving comfort during gear changes; Maintain high performance; and Increase the lifespan of the gears and shafts in the gearbox.

Claims

DEMANDS

1. A method (100) for regulating engine torque produced by an internal combustion engine of a powertrain equipped with a mechanical gearbox, a mechanical clutch, and control means, said method (100) being characterized in that, during the acceleration phase of said powertrain, it comprises the steps, executed by said control means, of - Detect (101) a desire to move from a speed ratio N to a higher speed ratio N+n; - Degrade (102) the nominal ignition advances of said internal combustion engine: o so as to reduce the engine torque produced by said internal combustion engine until the engine torque is between a minimum torque threshold (S1) and a maximum torque threshold (S2), o by applying an ignition advance control profile (P1), said profile (P1) comprising:

1. During a first time window (T1), a sudden degradation of the nominal ignition advances; 2. During a second time window (T2) following said first time window (T1), a progressive degradation ramp of said ignition advances until the engine torque is between the minimum torque threshold (S1) and the maximum torque threshold (S2); 3. During a third time window (T3) following said second time window (T2), an operating profile during which the motor torque is between the minimum torque threshold (S1) and the maximum torque threshold (S2).

2. Method (100) according to the preceding claim, characterized in that the minimum torque threshold (S1) is less than ONm and the maximum torque threshold (S2) is greater than ONm. [Claims] A method (100) according to any one of the preceding claims, characterized in that the operating profile during which the engine torque is between the minimum torque threshold (S1) and the maximum torque threshold (S2) corresponds, for each cylinder of the internal combustion engine, to the production of a spark at the spark plug occurring between 0° and +15° after the top dead center of a piston of said cylinder.

4. Method (100) according to any one of the preceding claims, characterized in that the ignition advance regulation profile (P1) includes, during a fourth time window (T4) successive to the third time window (T3), a progressive catch-up ramp of the nominal ignition advances.

5. Vehicle comprising a powertrain equipped with an internal combustion engine, a mechanical gearbox, a mechanical clutch and control means, said vehicle being characterized in that said control means are arranged to perform the steps of the process (100) according to any one of the preceding claims.

6. Product computer program downloadable from a communication network and / or recorded on a computer-readable medium and / or executable by a processor, characterized in that it includes program code instructions for implementing the method (100) according to any one of claims 1 to 4, when the program is executed on a computer.

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